MR imaging of squamous cell carcinoma of the floor of the mouth. Appearance of the sublingual and submandibular glands.

PURPOSE: To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands. MATERIAL AND METHODS: Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. The appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively. RESULTS: All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images. CONCLUSION: At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images.     

Carcinoma showing thymiclike differentiation (CASTLE tumor).

A 67-year-old woman had had a neck mass for 10 years, which recently increased in size. Sonographic, CT, and MR examinations showed a mass in the carotid and posterior spaces (triangle) extending from below the submandibular gland to the supraclavicular fossa, displacing the common carotid artery and the sternomastoid anteriorly. The mass was solid, noncalcified with lobulated outlines, hypoechoic on sonograms, of soft-tissue density on CT scans, isointense on T1-weighted MR images, hyperintense on T2-weighted MR images, and enhanced mildly after injection of contrast material on CT and MR studies. Histologic examination revealed a carcinoma showing thymiclike differentiation, a rare tumor of the neck and thyroid gland.     

Basal cell adenoma in the parapharyngeal space: MR findings

We report MR findings of a case of basal cell adenoma arising in the parapharyngeal space. On MR imaging, the mass was a well-circumscribed cystic and solid tumor with a thin fibrous capsule and intratumoral hemorrhage. It was confined to the parapharyngeal space, separating from the deep lobe of the parotid gland. The solid portion of the tumor was slightly hypointense/hyperintense to the muscle on T1-/T2-weighted images and was relatively well enhanced on Gd-enhanced T1-weighted images. The cystic contents of the mass were hyperintense on both T1- and T2-weighted images and were proven to be a hemorrhage.     

Basal cell adenoma of the parotid gland: dynamic CT and MRI findings

Imaging findings in basal cell adenoma (BCA) of the parotid gland have been rarely reported. We report dynamic CT and MRI findings of BCA in the parotid gland in a 78-year-old woman. Dynamic CT study demonstrated strong multinodular contrast enhancement in the early phase which decreased gradually in the later phases. The mass was isointense on T(1) weighted and hyperintense on T(2) weighted MR images with a central haemorrhagic-necrotic component. The microscopic findings were consistent with membranous type BCA.     

MR涎管造影初探

目的：估价ＭＲ涎管系统成像的技术和临床应用。材料与方法：用ＭＲ重Ｔ２加权技术加特别长的ＴＥ，回波时间７５０毫秒，采用脂肪抑制，厚层扫描，快速采集。检查了１７例，其中１４例无症状者，３例可疑涎管异常者。结果：无症状者１４例均清楚显示腮腺主导管。颌下腺主导管展示，但欠连续。３例可疑异常者中，１例示左颌下腺导管受压移位，手术证实为鳞癌。其余２例未见异常征象。结论：ＭＲ涎管造影能成功地显示腮腺和颌下腺导管系统，是一种非侵袭性检查方法，经进一步提高质量后相信有临床实际应用价值。     

Basal cell adenoma in the parotid gland: CT and MR findings

Basal cell adenoma is a rare benign salivary gland epithelial tumor, usually involving the parotid gland. We report CT and MR findings of three cases with basal cell adenoma occurring in the parotid gland. The three cases presented here demonstrate a well-circumscribed tumor, which showed a cystic and solid, or the pure solid mass. They were well enhanced after contrast matter injection. The solid portion of the mass was isoattenuated at CT, with intermediate signal intensity on T1- and T2-weighted MR images. Its cystic portion was hyperintense on both T1- and T2-weighted MR images. It had a hypointense rim on T2-weighted image.     

MR涎管造影临床研究及应用

目的 评价MR涎管造影的各种序列技术和临床应用。方法 依次采用短时反转恢复序列(STIR)、重T2加权快速自旋回波序列(重T2WIFSE)、单次激发快速自旋回波序列(SSFSE)，厚层扫描，快速采集，于服用维生素C(VitC)前后分别扫描。检查了30例，其中13例为志愿者，17例为可疑涎管异常者。结果 3种序列均能显示正常腮腺和颌下腺主导管。13例志愿者STIR序列均能清晰显示涎管1级和2级分支，2例能显示管径约为0．8mm的末梢分支；重T2WIFSE序列可清晰显示13例志愿者1级分支、10例2级分支；SSFSE序列可显示10例涎管1级分支、6例2级分支。STIR序列能清晰显示患者主导管和涎管1、2级分支；重T2WIFSE序列清晰显示患者12例涎管1级、8例2级分支；SSFSE序列清晰显示患者10例1级分支、4例2级分支。17例可疑异常者，腺体炎症7例，急性炎症主导管稍增粗，末梢导管呈点、球状扩张；颌下腺癌1例，导管受压移位，呈截断状改变；良性肿瘤7例，涎管受压移位，无中断；干燥综合征及涎腺病各1例，涎管未见明显异常。16例患者含服VitC0．2g后5min重复扫描，涎管显示较前增粗。结论 MR涎管造影能清晰显示腮腺和颌下腺导管系统，其中STIR序列能清晰显示导管2级分支，是1种显示涎管的非侵袭性方法，含服VitC后可使唾液分泌增多，从而使涎管显示率增加，具有较高的临床实用价值。     

Acinic cell carcinoma of the head and neck: radiologic-pathologic correlation

OBJECTIVE: To describe and correlate the imaging and pathologic findings of acinic cell carcinoma (ACC) in the head and neck. METHODS: We reviewed the radiologic findings of 12 patients with pathologically proven ACC in the head and neck. They were 6 males and 6 females (ages: 5-75 years, mean 36 years) who undergoing computed tomography (CT, n=9) and CT with magnetic resonance (MR) imaging (n=3). RESULTS: The lesions in the superficial lobe of the parotid gland were solid (n=7), cystic (n=1), and cystic mass with mural nodule (n=1) on CT. A parapharyngeal lesion was cystic mass with mural nodule, and a submandibular and a palate tumor were cystic lesions on CT. All solid masses in the parotid gland (n=7) included focal low-attenuating portions on CT, which were microcyst, hemorrhage, or necrosis on pathologic examination. We could not find intratumoral calcifications or metastatic lymphadenopathy on imaging and histologic studies in all 12 cases. Internal hemorrhage on the MR images was seen in a parapharyngeal and a parotid lesion. CONCLUSION: Although ACC appears to have nonspecific imaging findings, familiarity with some imaging features can be helpful for differential diagnosis of head and neck tumors.     

Diagnosis of aneurysm of superior thyroid artery by CT and MR imaging.

A 51-year-old man presented with a nonpulsatile anterior neck mass which suggested a thyroglossal duct cyst. At CT a small cystic mass was revealed. The mass contained a well-defined, crescent-shaped, low-density area with homogeneous contrast enhancement. On MR T2-weighted spin-echo and gradient-echo images the mass was as hyperintense as the neck vessels. Angiography and operation confirmed an aneurysm of the left superior thyroid artery with a mural thrombus.     

Tongue abscesses: MR imaging findings

BACKGROUND AND PURPOSE: A lingual abscess is difficult to diagnose in the absence of physical signs. MR imaging may provide an excellent and invaluable adjunct to clinical examination, but the literature is incomplete in defining the various MR imaging findings of abscess. The objective of this study was to determine the MR imaging features of tongue abscesses. METHODS: Seven surgically proved tongue abscesses were evaluated with MR imaging. Four patients underwent MR imaging because of suspected tumor, and 3 patients, to show the extent and precise anatomic location of the lesion. Lesions were assessed with regard to the location, size, signal-intensity characteristics, and pattern of contrast enhancement. RESULTS: Five lesions were located in the anterior tongue and 2, in the posterior tongue. The central parts of 4 anterior tongue abscesses were hypointense, surrounded by a hyperintense wall on T1-weighted precontrast images. On postcontrast images, marked wall enhancement was detected. On T2-weighted images, a markedly hyperintense central part surrounded by a hypointense rim was seen. In 2 of these patients, there was a hypointense halo surrounding the wall (target sign). In 3 patients, a perilesional hyperintense area that enhanced diffusely after contrast administration was detected on T2-weighted images. The smallest lesion located in the anterior tongue was hypointense on T1-weighted images and enhanced diffusely on postcontrast images. On T2-weighted images, a markedly hyperintense central part surrounded by a mildly hyperintense peripheral part was depicted. Posterior tongue lesions appeared as polypoid ill-defined masses and were hypointense on T1-weighted images and heterogeneously hyperintense on T2-weighted images. On postcontrast images, the lesion in 1 patient showed diffuse and heterogeneous contrast enhancement, whereas the lesion in another patient enhanced peripherally. The lesions were totally excised in 4 patients and drained with surgical incisions in 3 patients. No recurrence was detected on follow-up. CONCLUSION: An abscess typically presents as a cystic lesion surrounded by an enhancing capsule formation, but lesions may also present as solid masses that enhance diffusely or peripherally.     

Plunging ranula: CT diagnosis

A plunging ranula is a cystic mass in the submandibular area arising from an occluded sublingual gland. Fluid from the obstructed gland dissects between the fascial planes and muscle of the base of the tongue to the submandibular triangle. A plunging ranula can be readily identified preoperatively with computed tomography as a cystic mass in the suprahyoid anterior neck. Three case reports are presented.     

MR扩散加权成像对颅内囊性肿块的鉴别诊断价值

目的 :探讨MR扩散加权成像对颅内囊性肿块的鉴别诊断价值。方法 :搜集有手术病理结果的患者 3 1例 ,其中表皮样囊肿 9例 ,蛛网膜囊肿 15例 ,囊性颅咽管瘤 4例 ,颅底囊性变神经鞘瘤 3例。所有病例均行MR常规T1WI、T2 WI及DWI扫描 ,回顾性分析各组病例的MR常规及扩散加权成像表现。结果 :在MR扩散加权图像上 ,所有 7例表皮样囊肿均为显著高信号 ,而在指数扩散加权像及ADC图上为等信号 ;其余病变在扩散加权图像上为低信号或伴等信号。结论 :MR扩散加权成像有助于表皮样囊肿与其它颅内脑外囊性肿块的鉴别 ,表皮样囊肿的扩散加权高信号主要是由“T2余辉效应”而非水分子扩散受限所致。     

Ectopic cervical thymus in an infant

We report a case of accessory cervical thymus presenting as a unilateral neck mass in a 2-month-old boy. Ultrasonography (US) showed a mass isoechogenic to muscle in the left neck. Computed tomography (CT) revealed a well-defined, mildly enhanced mass located anterior to the sternocleidomastoid muscle, anterolateral to the carotid sheath, and posterior to the submandibular gland. On magnetic resonance imaging (MRI), the mass was isointense to muscle on T1-weighted images and hyperintense to muscle on T2-weighted images. Diffusion-weighted images showed relatively low apparent diffusion coefficient (ADC) values, and the mass was slightly enhanced after administration of contrast material. We suspected ectopic thymus, but we could not exclude the possibility of a malignant lesion. Therefore, the tumor was surgically resected. The histological diagnosis was ectopic cervical thymus. Ectopic thymus should be included in the differential diagnosis of a submandibular or cervical mass in infants. US and MRI can provide useful information for the diagnosis of ectopic cervical thymus.     

MRI findings in lingual venous malformations

OBJECTIVES: To describe the plain and enhanced MRI findings of lingual venous malformations and to discuss the importance of contrast medium in the differential diagnosis of high intensity lesions of the tongue on T(2) weighted images. METHODS: The clinical records and MR images of eight patients affected by a lingual venous malformation were retrospectively reviewed. Patients presented with a palpable submucosal bluish-red soft mass in the tongue. MRI examinations were performed on a 0.5 T superconducting unit. Plain and enhanced SE (spin echo) T(1) weighted and FSE (fast spin echo) T(2) weighted images were acquired in axial, sagittal and coronal planes. Axial SPGR (spoiled gradient recalled echo) T(1) weighted images were also obtained before and after intravenous (i.v.) injection of paramagnetic contrast medium. RESULTS: Five of eight venous malformations were located at the tip of the tongue. The other three involved the whole tongue and had an extralingual extent; two extended into the submandibular space and one into the glossoepiglottic valleculae. The largest diameter ranged from 2.5 cm to 8 cm. All lingual venous malformations presented as lobulated masses that were slightly hyperintense or isointense on T(1) weighted images and highly hyperintense on T(2) weighted images with respect to normal tongue and/or surrounding muscles. They showed a slow and homogeneous filling following iv injection of contrast medium. Millimetre-sized hypointense foci and linear hypointense strands were sometimes noticed, which were owing to phleboliths, flow void or septation. CONCLUSION: Knowledge of MRI findings of lingual venous malformations is useful for differential diagnosis with other high intensity lingual lesions on T(2) weighted images. This discrimination is achievable using iv paramagnetic contrast medium.     

Ranulas and their mimics: CT evaluation

The spectrum of computed tomographic (CT) findings in ten patients with pathologically proved simple and diving ranulas is reviewed. These retention cysts originate within the sublingual space from obstruction of the sublingual or minor salivary glands; when they enlarge, the cysts herniate to involve the submandibular and inferior parapharyngeal spaces (the so-called diving or plunging ranula). CT findings in 38 additional patients with a variety of cystic lesions in the floor of the mouth are contrasted with findings in cases of ranulas. The relevant anatomy is reviewed. This experience indicates that a unilocular, cystic mass emanating from the sublingual space and extending into the adjacent submandibular and/or inferior parapharyngeal spaces can be considered a diving ranula in virtually all cases. A unilocular, cystic mass entirely within the sublingual space can be considered a simple ranula in most instances, although absolute distinction between a simple ranula and an epidermoid cyst cannot be made radiographically.     

Differential diagnosis of submandibular cystic lesions by computed tomography

A retrospective analysis of 35 submandibular cystic lesions was undertaken to assess the usefulness of CT in their differential diagnosis. Lesions were analysed on the basis of extent, shape and density. It was found that all those lesions that extended into both the sublingual and the anterior part of the submandibular spaces could be diagnosed as ranulas (10/10) and all those limited to the posterior part as lateral cervical cysts (8/8). Those lesions that extended to the sublingual, but not the anterior part of the submandibular space, were dermoid cysts if they had a smooth margin (2/2), and probably ranulas when it was concave (4/5). Those lesions that extended into the anterior part of the submandibular but not the sublingual space were ranulas on the basis of a multilocular or concave margin (3/3), but if they had a smooth margin (3/7) they could not be differentiated from dermoid cysts (4/7). Although CT density was less valuable for the differential diagnosis, both ranulas and dermoid cysts could be excluded if it was similar to that of muscle.     

MRI of chronic sclerosing sialoadenitis

The purpose of our study was to describe the MR appearance of Kuttner's tumours and to interpret their differences in appearance from other submandibular gland tumours. MR studies of 7 Kuttner's, 8 malignant and 12 benign submandibular gland tumours were reviewed. MR sequences obtained included T(1) weighted, short inversion time inversion recovery (STIR), T(2) weighted, diffusion-weighted (DW) and dynamic contrast-enhanced MR (dynamic MR) images. In all cases of Kuttner's tumour, the affected submandibular glands were swollen with slightly higher intensity on T(2) weighted, STIR and DW images, but the tumour margin could not be defined. Conversely, the margins of the other tumours could be detected. On T(2) weighted, STIR and DW images, the mean signal intensity ratios and the mean apparent diffusion coefficient (ADC) values for Kuttner's tumours and malignant tumours were significantly lower than those of benign tumours, but there were no significant differences between those of Kuttner's tumours and those of malignant tumours. All benign tumours showed late enhancement, with peak enhancement later than 120 s on dynamic MR images. Kuttner's tumours and malignant tumours showed variable enhancement patterns. In conclusion, signal intensity ratios for T(2) weighted and STIR images, ADC values and patterns of enhancement may help distinguish Kuttner's tumours from benign submandibular gland tumours, but not from malignant tumours. Although the intensities, ADC values and enhanced patterns of Kuttner's tumours were similar to those of malignant tumours, there were some morphological differences.     

A case of cystadenocarcinoma of the ectopic salivary gland: comparison of pre-operative ultrasound, CT and MR images with the pathological specimen

Cystadenocarcinoma is a rare salivary gland tumour. Only a few case studies have provided pre-operative images of these tumours. This report demonstrates the case of a 28-year-old male with cystadenocarcinoma arising from an ectopic salivary gland with lymph node metastasis in the right upper neck. Ultrasound including Doppler images showed two masses with scant vascular flow. One was a hyperechoic mass enclosed within a low echoic cystic lesion and the other was a solid hypoechoic mass. Contrast enhancement CT scans demonstrated a ring enhanced mass and weakly homogeneous enhanced masses in the right upper neck. Dynamic studies showed increased enhancement in delayed phase CT that was the same as that in other malignant salivary gland tumours. Moderate to slightly high signal intensity was seen on T(1) weighted MR images and axial T(2) weighted MR images showed one heterogeneous mass in a high signal lesion and a moderate to high signal intensity mass. The authors discuss the pre-operative findings of ultrasound with Doppler imaging of this neoplasm, and CT findings including dynamic study images and MRI, comparing the findings with the post-operative pathological features of the tumour.     

MR of the submandibular gland: normal and pathologic states.

PURPOSETo evaluate the MR appearance of normal and pathologic states of the submandibular gland.METHODSMR images of 22 healthy subjects and 21 patients with histopathologically confirmed disorders of the submandibular gland (five pleomorphic adenomas, two hemangiomas, two malignant lymphomas, one adenoid cystic carcinoma, one squamous cell carcinoma, and 10 cases of sialadenitis) were reviewed.RESULTSAll normal submandibular glands showed higher signal intensity than surrounding muscle but lower intensity than fat on T1-weighted and T2-weighted images. Postcontrast images showed moderate enhancement of the gland. All the tumors had lower signal intensity than the normal submandibular gland on T1-weighted images and had intermediate to high (n = 8) or high (n = 3) signal intensity relative to the normal submandibular gland on T2-weighted images. Six of seven benign tumors were well defined, and three of four malignant tumors were poorly defined. In all cases of sialadenitis, the submandibular gland showed diffusely different signal intensities from the normal gland on both T1-weighted and T2-weighted images. Eight cases of chronic sialadenitis showed lower T2-weighted signal intensities than the normal gland, and this can be explained histopathologically by marked fibrosis and cellular infiltration.CONCLUSIONSMR imaging can show the presence, extent, margins, and signal intensity changes of pathologic conditions of the submandibular gland.     

MR imaging of the pituitary gland in infants and children: changes in size, shape, and MR signal with growth and development.

It has been reported that on MR images of the brain in neonates the entire pituitary gland is hyperintense. This is quite different from the well-established observation that portion is isointense. To better understand the development of the neonatal pituitary gland, we studied the timing and magnitude of changes in the size, shape, and MR signal of the pituitary gland in early childhood and infancy. The study included 76 infants and children ages 3 days to 4 years old. In each MR study, the signal intensity of the pituitary gland on T1-weighted coronal (n = 24) and sagittal (n = 76) images was compared with the signal intensity of the pons by using region-of-interest methods. The size and shape of the pituitary glands were recorded. Statistical comparisons were made for signal intensity and size of the pituitary gland between boys and girls and among age groups. The results showed that the MR signal of the posterior lobe remained hyperintense relative to the pons for all age groups represented in our study (through 4 years). However, the signal intensity of the anterior lobe gradually diminished and by approximately age 2 months was isointense with the pons. Thus, by approximately age 2 months the MR signal intensity of the infant's pituitary gland has changed from being entirely hyperintense (as seen in neonates) to isointense in the anterior lobe and hyperintense in the posterior lobe (as seen in adults). In the first 2 months of life the pituitary gland is bulbous in shape; later it has a flatter upper surface. We found no significant changes in the length or signal intensity of the pituitary gland; no differences among sexes in size, shape, or signal intensity were demonstrated. Findings of a bulbous pituitary gland and high MR signal of the entire pituitary are normal in neonates up to 2 months of age. After that, the gland gradually flattens and the MR signal of the anterior lobe decreases until it has characteristics similar to the adult pituitary. Lack of high signal or discovery of a small pituitary gland in a neonate should alert the radiologist to the possibility of pituitary malformation or dysfunction.